It is known to replace damaged human ligaments by a synthetic material such as a synthetic polyester fiber made from methyl terephthalate and ethylene glycol, commercially produced under the trademark "Dacron". Such synthetic substitutes are effective for a time, but after a long period, they tend to disintegrate.
Non-synthetic ligament substitutes have been used such as a tendon taken from an animal and appropriately fixed in a fixing solution such as glutaraldehyde. As in the case of synthetic substitutes, however, it is found that tendons similarly do not last a sufficient length of time as to be really effective.